1N4549RB

Single Zener Diodes Overview

The Microchip Technology 1N4549RB is a high-power 50 W Zener diode with a nominal voltage of 3.9 V and a tolerance of +/- 5%. It features reverse polarity, connecting the cathode to the case, indicated by the 'R' suffix. The device operates within a junction temperature range of -65°C to +175°C and utilizes a DO-5 (DO-203AB) metal-glass package. Maximum DC current is 11,900 mA at a test current of 3,200 mA.

Single Zener Diodes Feature Summary

• Hermetically sealed welded construction for environmental protection
• Internal solder bond construction for mechanical stability
• Reverse polarity design with cathode connected to the case
• Inherently radiation hard per Microsemi MicroNote 050

Single Zener Diodes Applications

• Voltage regulation in military and aerospace systems
• High power dissipation applications requiring low thermal resistance
• Circuits demanding ESD non-sensitivity per MIL-STD-750 Method 1020

Single Zener Diodes Procurement Notes

Verify the specific ordering suffixes against the datasheet to confirm the reverse polarity designation and tolerance level. Ensure that mounting hardware requirements align with the hexagonal stud specifications. Confirm compliance with relevant military qualification standards if required for the intended application environment.

Single Zener Diodes Selection Notes

Select this component when a 3.9 V reference with high power handling is needed. The reverse polarity configuration allows the case to serve as the cathode terminal. Verify that adequate heat sinking is provided to maintain the case temperature below 75°C for full 50 W operation.

Single Zener Diodes Part Context

This part belongs to the 1N4549B through 1N4556B series of 50 W Zener diodes manufactured by Microsemi (now Microchip Technology). These devices are JEDEC registered and available in various military screening levels including JAN, JANTX, and JANTXV qualifications.

Single Zener Diodes Replacement Considerations

Equivalent parts include the standard 1N4549B for standard polarity or other 1N4549 variants with matching voltage and power ratings. Verify polarity orientation carefully when substituting.